9 papers
A Quantum Field Theory Twist to Photon Angular Momentum
G. F. Calvo, A. Picon, E. Bagan
A quantum field theory approach is put forward to generalize the concept of classical spatial light beams carrying orbital angular momentum to the single-photon level. This quantiz…
Aligning Spatial Frames Through Quantum Channels
E. Bagan, R. Munoz-Tapia
We review the optimal protocols for aligning spatial frames using quantum systems. The communication problem addressed here concerns a type of information that cannot be digitalize…
Optimal reconstruction of a pure qubit state with local measurements
E. Bagan, M. Baig, A. Monras +1
We analyse the reconstruction of an unknown pure qubit state. We derive the optimal guess that can be inferred from any set of measurements on N identical copies of the system with…
Communicating a direction using spin states
E. Bagan, M. Baig, R. Munoz-Tapia
The communication of directions using quantum states is a useful laboratory test for some basic facts of quantum information. For a system of spin-1/2 particles there are different…
Effective Quarks and Their Interactions
Emili Bagan, Robin Horan, Martin Lavelle +1
This talk will summarise the progress we have made in our programme to both characterise and construct charges in gauge theories. As an application of these ideas we will see how t…
Charged Matter: Physics and Renormalisation
Emili Bagan, Martin Lavelle, David McMullan
Descriptions of the ground state in unbroken gauge theories with charged particles are discussed. In particular it is shown that the on-shell Green's functions and S-matrix element…